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troj

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I've never tried heading a casing to remove a stuck liner.

What I have done is used something sharp to get under the edge of it and break some pieces out that way, then take a closure (delay module would work) without o-rings and use that, in conjunction with a dowel, to drive the liner out.

-Kevin
 

lmt56

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I have tried freezing before with out much luck.
I did have the oven method work on a AMW csae and once used a propane tourch, carefully, on a AeroTech csae.
No damage to either.
Sometimes you have to take a chance.
Unless you get the liner out the case is not much use.
I have not had any trouble with CTI cases.
 

Reinhard

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If I interpret the chart correctly, heating the casing will cause the phenolic to expand faster than the case. Freezing it might be a better option as it should shrink faster than the metal.

https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

Linear Temperature Expansion Coefficients
Aluminum 12.3
Steel 7.3
Phenolic resin without fillers 44.4

I don't know it exactly, but the expansion coefficient of phenolic will be reduced significantly by the filler material. It might end well below that of aluminum, therefore making heating the better option.

Reinhard
 

n3tjm

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Did you grease the liner when you assembled the pro54? Most Grease turns to glue after the motor fires.

Glad to see you got the liner out.
 
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cjl

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Honestly, with the CTI motors, I usually just push harder :)

If you get a dowel, stick it against the forward closure, and beat on the dowel with a hammer, it'll push everything out. I've yet to have one where that was insufficient (though it has taken quite a bit of beating sometimes).
 

THier

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Congrats on saving the case, one problem though, what are you going to do when the casing is too large for the oven? I use a heat gun, works great. I have a 6000ns case I got for REAL cheap, as the ID is a little small, so liner is tight. I have to use this method often.

Tom
 

tomar

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This thread caught my attention. I've been having the same issue with an Ellis Mountain 6000 liner and case. I gladly share my experience.

The EM 6000 case is a 76mm case for the M1000 load (too bad EM motors are going into extinction).

The phenolic liner was greased during assembly and the flight was nominal. We lost the rocket during recovery and it was a few months before someone found the rocket at the launch site. We immediately found the liner stuck in the case.

We used a 1.5" Oak dowel with sharp angle cut on one end and a rubber mallet to break out the phenolic. That worked about 1 foot into each end. The center part of the liner would not chip out.

Be careful using the forward closure and a large dowel to beat/push the liner out (with O-rings in place). We discovered the forward closure was damaging the interior wall of the case so I stopped that.

We tried putting the case in the freezer, but that did not work.

We tried leaving the case out in the Arizona summer sun to heat it up, but that did not work either.

We tried a propane torch to heat the case, but that did not work either.

We tried a heat gun, but hat did not work either.

We tried all manner of solvents, but that did not work either

I'm not giving up on this case as it will make a nice EX case even though there will be no more EM reloads soon.

One thing we have not tried, but may be a near last resort it taking it to an auto mechanic shop that has a vat for "boiling" engine blocks. What ever that solution is, it takes off gasket material which as been sealed and torqued on. That might work. I'll find out what that solution is and check with motor manufacturers first.
 

jimzcatz

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Tomar,I believe Ed Romani at Tru-core has a lathe that will cut the liner out. Check with him.
 

tomar

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Jim,

Thanks for the tip. I'll look into it.
 

bobkrech

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I'd suggest you find someone with a hydraulic press. Use the press to push the forward closure into the casing and push the liner out the other end. Soaking the casing in Simple Green befroe doing this may reduce the stiction.

Liners should come out easily if removed shortly after use. The easiest way to get the liner out at the field is to remove the nozzle, and then invert the motor and bang against the forward closure to push the liner out throught the aft end of the casing. If you are using a threaded forward closure, get a wooden closet rod or metal rod, thread the end for a stud, and screw it to the forward closure. Hold the casing and pound the rod into the ground. This should remove all but the most stubborn liners.

If this should fail, use the hydraulic press to push harder.

Bob
 

rdmmdr

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if your closure has a nice radius on the aft end it can climb into the liner a swell the case using a press. a good penetrating oil soaking for a couple of day will probably do wonders
 

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